Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 30,503,403	$ 13,920,152
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,576,441	3,579,474
Stock-based compensation expense	1,196,361	1,156,929
Provision for doubtful accounts		24,098
Provision for inventory	220,207	165,803
Gain on sale of assets		(442,341)
Tax benefit from exercise of stock options	(9,236,708)	(764,181)
Changes in operating assets and liabilities:
Accounts receivable	(1,840,407)	4,667,839
Inventories	(2,923,628)	(3,430,655)
Prepaid expenses, other current and long-term assets	183,481	531,449
Long-term deposits and other		25,497
Accounts payable	(992,822)	124,679
Accrued expenses	(989,291)	(642,430)
Deferred revenue	(2,078,543)	(2,150,000)
Income taxes	7,771,001	766,598
Other long-term liabilities	(167,123)	(373,712)
Net cash provided by operating activities	25,222,372	17,159,199
Cash flows from investing activities:
Purchase of marketable securities	(19,999,169)	0
Proceeds from sale of assets		530,865
Purchase of property and equipment	(920,132)	(235,803)
Net cash provided by (used in) investing activities	(20,919,301)	295,062
Cash flows from financing activities:
Proceeds from exercise of stock options	1,379,294	2,932,649
Tax benefit from exercise of stock options	9,236,708	764,181
Minimum tax withholding on share based awards	(6,348,900)
Principal payments on debt		(1,200,000)
Net cash provided by financing activities	4,267,102	2,496,830
Exchange rate impact on cash	(131,139)	36,870
Increase in cash and cash equivalents	8,439,034	19,987,961
Cash and cash equivalents at beginning of period	63,333,160	44,067,477
Cash and cash equivalents at end of period	$ 71,772,194	$ 64,055,438